Expandable cardiac harness for treating congestive heart failure

Abstract

A cardiac harness for treating congestive heart failure is disclosed. The harness applies elastic, compressive reinforcement on the left ventricle to reduce deleterious wall tension and to resist shape change of the ventricle during the mechanical cardiac cycle. Rather than imposing a dimension beyond which the heart cannot expand, the harness provides no hard limit over the range of diastolic expansion of the ventricle. Instead, the harness follows the contour of the heart throughout diastole and continuously exerts gentle resistance to stretch. Also disclosed is a method of delivering the cardiac harness to the heart minimally invasively.

What is claimed is:  
     
       1. A cardiac harness, comprising: 
       first and second strands of material each having a plurality of hinges, each of said hinges formed by a pair of arm portions extending from a central portion, each hinge within said plurality of hinges of the first strand having both arm portions disposed within a hinge of the second strand, between the arm portions of said hinge of the second strand.  
     
     
       2. The cardiac harness of  claim 1 , wherein at least one of said hinges comprise Nitinol. 
     
     
       3. The cardiac harness of  claim 1 , wherein at least one of said strands comprises a band. 
     
     
       4. The cardiac harness of  claim 1 , wherein hinges in the first and second strands are elastically deformable in a first direction. 
     
     
       5. The cardiac harness of  claim 4 , wherein the first and second strands are movable relative to each other in a second direction over a range of positions, the second direction being substantially perpendicular to the first direction. 
     
     
       6. The cardiac harness of  claim 4 , wherein the harness is formed of an elastically deformable material. 
     
     
       7. The cardiac harness of  claim 6 , wherein the harness is formed of a metal. 
     
     
       8. A method of assembling a cardiac harness, comprising: 
       providing a plurality of rings, each of said rings sized to surround a ventricle of a heart, each of said rings having a series of periodic undulations, each of said rings being unattached to other of said rings; and  
       interconnecting the rings by interleaving said undulations without interrupting continuity of the rings.  
     
     
       9. The method of  claim 8 , wherein at least one of said rings comprises Nitinol. 
     
     
       10. A cardiac harness for placement around at least a portion of a patient's heart, comprising: 
       a first strip having a first series of continuous periodic undulations and a second strip having a second series of continuous periodic undulations, the strips being elastically deformable in a first direction and being arranged substantially adjacent and parallel to each other;  
       wherein at least some of the undulations of the first strip are interwoven with at least some of the undulations of the second strip so that the first strip is movable in a second direction relative to the second strip over a limited range, said second direction orthogonal to the first direction.  
     
     
       11. The cardiac harness of  claim 10 , wherein the undulations are elongate in the first direction. 
     
     
       12. The cardiac harness of  claim 11 , wherein the undulations are elastically deformable in the first direction. 
     
     
       13. The cardiac harness of  claim 10 , wherein the first and second strips are movable relative to each other in the second direction substantially without resistance over the range. 
     
     
       14. The cardiac harness of  claim 10 , wherein the first and second strips are sized and configured to extend substantially around a patient's heart so that the undulations are elastically deformed and collectively exert an inwardly-directed compressive force on the heart during at least a portion of the cardiac cycle. 
     
     
       15. The cardiac harness of  claim 14 , wherein the cardiac harness is sized to exert an inwardly-directed compressive force throughout the entire cardiac cycle. 
     
     
       16. The cardiac harness of  claim 14 , wherein the undulations are arranged and configured so that they deform in a direction substantially transverse to a longitudinal axis of the heart. 
     
     
       17. The cardiac harness of  claim 14 , wherein the inwardly-directed force is generally less than about 10 mmHg.